Table 2.

 Summary relative risk estimates (95% confidence intervals) for coronary heart disease (CHD) events and stroke from randomised blood pressure difference trials observed and standardised to a blood pressure reduction of 10 mm Hg systolic and 5 mm Hg diastolic

Clinical history of participants on entry	No of trials	Observed			Standardised for blood pressure reduction
		CHD events	Stroke		CHD events	Stroke
No vascular disease	27	0.84 (0.79 to 0.90)	0.64 (0.56 to 0.73)		0.79 (0.72 to 0.86)	0.54 (0.45 to 0.65)
CHD*	37	0.85 (0.79 to 0.91)	0.77 (0.68 to 0.87)		0.76 (0.68 to 0.86)	0.65 (0.53 to 0.80)
Stroke	13†	0.85 (0.73 to 1.00)	0.76 (0.68 to 0.85)		0.79 (0.62 to 1.00)	0.66 (0.56 to 0.79)
All trials*	72	0.84 (0.81 to 0.88)	0.70 (0.65 to 0.76)		0.78 (0.73 to 0.83)	0.59 (0.52 to 0.67)

*Summary estimates omitting CHD events (but not strokes) in trials of β blockers in patients with a clinical history of CHD (heterogeneity for CHD, χ²=0.02, df=2, P=0.99; heterogeneity for stroke, χ²=2.0, df=2, P=0.37).

†Includes subgroups of participants with stroke on entry from five predominantly “no vascular disease” trials so total is less than the sum of the individual categories^w5 (see web extra table 1iii).